A thin film transistor-liquid crystal display (TFT-LCD) includes a color filter substrate (CF Substrate) and a thin film transistor substrate (TFT Substrate), and transparent electrodes are provided on relative inner sides of the substrates. A layer of liquid crystal (LC) molecules are interposed between the two substrates. The display purpose of the liquid crystal display is achieved through an electric field controlling an orientation of the liquid crystal molecule to change polarization state of light, and by a polarizer implementing transmittance and barrier of light path.
It can be said that no matter current large, medium and small size display, LCD occupy absolute market thereof. In the current LCD application market, terminal display equipment of shopping malls, supermarkets, hotel lobbies, theaters, education, health care and other public places of crowd gathering get more and more demand and application, which are growing at an annual rate of more than 30% growth.
On the other hand, polymer dispersed liquid crystal (PDLC) as a LCD dimmer has been widely concerned and used. PDLC is a material which is obtained by mixing low molecular liquid crystal and prepolymer, forming micron level liquid crystal droplets uniformly dispersed in a polymer network through polymerization under a certain condition, and obtaining electro-optical response characteristic by utilizing dielectric anisotropy of the liquid crystal molecules, its main work is to have certain gray between scattering state and transparent state. A PDLC liquid crystal display has a lot of advantages, such as no need of a polarizer and an alignment layer, a simple fabrication process, easy to fabricate a large area flexible display, etc.; now, it has obtained wide applications in optical modulators, thermal sensitive and pressure sensitive devices, electronic control glass, light valves, projection displays, electronic books, and other aspects. The work principle thereof is that regular electric field cannot form between films without an applied voltage, optical axis orientations of liquid crystal micro particles are random and show disorder state, and an effective refractive index n0 thereof does not match a refractive index np of the polymer. Incident light ray is strongly scattered, the thin film presents opaque or semi-transparent. After applying the external voltage, the light axis of the liquid crystal micro particles are arranged perpendicular to a surface of the thin film, i.e. identical to the electric field direction. An ordinary refractive index of the micro particles substantially matches the refractive index of the polymer, there is no obvious interface, and it constitutes a substantially uniform medium, so scattering the incident light does not occur, and the thin film presents transparent. Therefore, PDLC has a characteristic of light switch when it is driven by the applied voltage; and with increasing the applied voltage, the degree of transparency increases along a certain curve type.
Additionally, graphene, which begins to reveal conspicuous application in TFT-LCD, is a major scientific discovery, following fullerene and carbon nanotube, as another mile stone in the nanomaterial research field. The graphene is a two-dimensional atomic crystal constituted by single atomic layer of linking carbon atoms with hybridized sp orbit, a basic structural unit thereof is the most stable six-membered ring structure of benzene, when electrons in the graphene move in the orbit, scattering will not occur due to lattice defects or introduction of foreign atoms. Due to the presence of π orbit in a plane of the graphene sheet, the electrons can freely move in the crystal, so that the graphene has very excellent electron transport properties. The graphene further has many special properties, such as zero energy gap, anomalous quantum Hall effect, the Landau quantum property, etc., so the graphene attracts more and more people in the flat display industry to research applications thereof.